A fuel cell is an energy conversion device that generates electricity and heat by electrochemically combining a gaseous fuel, such as hydrogen, carbon monoxide, or a hydrocarbon, and an oxidant, such as air or oxygen, across an ion-conducting electrolyte. The fuel cell converts chemical energy into electrical energy. A fuel cell generally consists of two electrodes positioned on opposite sides of an electrolyte. The oxidant passes over the oxygen electrode (cathode) while the fuel passes over the fuel electrode (anode), generating electricity, water, and heat. There are several types of fuel cells, including proton exchange membrane (PEM) fuel cells and solid oxide fuel cells (SOFC).
In a typical SOFC, a fuel flows to the anode where it is oxidized by oxygen ions from the electrolyte, producing electrons that are released to the external circuit, and mostly water and carbon dioxide are removed in the fuel flow stream. At the cathode, the oxidant accepts electrons from the external circuit to form oxygen ions. The oxygen ions migrate across the electrolyte to the anode. The flow of electrons through the external circuit provides for consumable or storable electricity. However, each individual electrochemical cell generates a relatively small voltage. Higher voltages are attained by electrically connecting a plurality of electrochemical cells in series to form a stack.
The fuel cell stack also includes conduits or manifolds to allow passage of the fuel and oxidant into and byproducts, as well as excess fuel and oxidant, out of the stack. Generally, oxidant is fed to the structure from a manifold located on one side of the stack, while fuel is provided from a manifold located on an adjacent side of the stack. The fuel and oxidant are generally pumped through the manifolds and introduced to a flow field disposed adjacent to the appropriate electrode. The flow fields that direct the fuel and oxidant to the respective electrodes, typically create oxidant and fuel flows across the electrodes that are perpendicular to one another.
The long term successful operation of a fuel cell depends primarily on maintaining structural and chemical stability of fuel cell components during steady state conditions, as well as transient operating conditions such as cold startups and emergency shut downs. The support systems are required to store and control the fuel, compress and control the oxidant and provide thermal energy management. A fuel cell can be used in conjunction with a reformer that converts a fuel to hydrogen and carbon monoxide (the reformate) usable by the fuel cell. Three types of reformer technologies are typically employed (steam reformers, dry reformers, and partial oxidation reformers) to convert hydrocarbon fuel (methane, propane, natural gas, gasoline, etc) to hydrogen using water, carbon dioxide, and oxygen, respectfully, with byproducts including carbon dioxide, carbon monoxide, and water, accordingly.
The fuel cell system is dependent upon the reformate created. Steam processing of fuels is efficient since it produces a greater amount of fuel per unit of pre-reformed fuel than the partial oxidation reformer. However, storage of water for supply to the fuel cell system requires a large amount of space, additional weight, and time-consuming maintenance.
The drawbacks and disadvantages of the prior art are overcome by water recovery for a fuel cell system.
A fuel cell system is disclosed. A fuel cell stack is in fluid communication with a reformer, which is in fluid communication with an air conditioning system.
A method of making a fuel cell system is also disclosed. The method comprises disposing a reformer in fluid communication with a fuel cell stack and disposing an air conditioning system in fluid communication with the reformer.
A method of using a fuel cell system is also disclosed. The condensate from an air conditioning system is directed to a reformer. The reformer is operated to produce a reformate and the reformate is utilized in a fuel cell stack to produce electricity.
A fuel cell system is disclosed. The fuel cell system comprises a means for producing electricity from a reformate, a means for producing the reformate from a condensate, and a means for producing the condensate from air.
A fuel cell system is disclosed. The fuel cell system comprises a proton exchange membrane fuel cell stack and an air conditioning system in fluid communication with the proton exchange membrane fuel cell stack.
A method of using a fuel cell system is disclosed. The method comprises producing a condensate in an air conditioning system and hydrating a proton exchange membrane fuel cell with at least a portion of the condensate.
The above described and other features are exemplified by the following figures and detailed description.